There's a bunch of realy good videos on YouTube one older white guy does an awesome job explaining it... You can use it sex your plant but idk about cloning just a top...
If you going to clones it just really take care of that clone, they are so delicate and even worst if is ur first time doing it, I f up alot of them lol =)
It all depends what you want to do and what strain it is. Everything I've run has taken well to it. I do it to everything. On seedlings I top just above the first set of leaves with 5 blades on it. I let it get tall enough so that single stem above the cut can be used as a cutting. It roots and I put it straight to 12/12 to sex the plant. Back to the seedling. You'll usually get 2 new shoots. Once in a while you'll come across plants that have 3 leaves early per node. In this case you'll get 3 new shoots. (As soon as the sex shows I chuck the males. Cutting and OG plant) Then the remaining females get looked over individually for overall height. With that in mind I take as many cuttings need to insure survival. The better you get at that the less you'll have to keep. This is the final topping so think of it like a head of hair. Lower branches not cut will grow faster than the new ones you took the cuttings from. In time you'll figure it out but the goal is that the lower branches are as close to the same hieght as the ones that were topped 14-18 days later without being taller. This way when I force flowering more branches are near the light. Theoretically I'm trying to accomplish the same thing as scrog. This also keeps the overall height down because this method takes longer. So you have to worry about stretch. Once I've found the keeper I still top but since I know the sex and it's mature you can accomplish the same thing in less time. And handle each strain as needed. I wouldn't treat a Nev haze the same way I would say AK47. But that comes later.
Cloning should be REALLY easy. Read up and keep the humidity around 60% and the temp in the mid to upper 70s. I started with Olivia's root get. Great results. Then I tried soaking the soil with dyna gro KLN. great results. Now I'm using KLN and protekt in a bubble system. Great results. But for what I'm doing I REALLY like the bubble system. I can use larger stemmed and much taller cuttings. So when I pull them out and put them in soil I can top them also. So while it's getting over the transplant stress it's also growing side branches for an over all time savings. It also saves me some soil thought the year keeping multiple strains alive in the library.